Fumigation with perfluorodimethylperoxide



United States Patent 3,294,634 FUMIGATION WITH PERFLUORODIIVIETHYL- PEROXIDE Everett E. Gilbert, Morristown, N.J., assignor to Allied Chemical Corporation, New York, N.Y., a corporation of New York No Drawing. Filed Sept. 23, 1965, Ser. No. 489,731 2 Claims. (Cl. 16739)' This invention is directed to the use of perfluorodimethylperoxide as a fumigant and, more particularly, to a process for the control of pest organisms by subjecting the pests to the vapor of perfluorodimethylperoxide.

As is known in the art, the control of pest organisms which infest hosts such as soil, \grain, fruits, vegetables, textiles, dwellings, warehouses and the like is extremely difficult in those cases where the pest organisms penetrate deeply into the interior of the host space. The use of surface poisons or pesticides for this purpose is not completely effective because of the difficulty in reaching the interior of the space. Although various fumigants have been proposed for controlling such pests, there is a need for new and highly effective fumigants.

I have now discovered that perfiuorodimethylperoxide is an outstanding fumigant exerting lethal effects, even in extremely small doses, against common penetrating pests such as those infesting plants, plant parts, grain, flour, carpets, etc.

Perfluorodimethylperoxide is a colorless gas boiling at 37 C. and thermally stable up to 225 C. It can be synthesized by more than one procedure. However, the preferred procedure appears to be the reaction of carbon monoxide with elemental fluorine or (which may be equivalent thereto) the reaction of trifluoromethyl hypofluorite a Patented Dec. 27, 1966 of the toxicant per thousand cubic feet of enclosed space is needed to permeate the area and to insure effective control of the pests. The exposure time required depends upon the size of the enclosed area andthe type of host, e.g. flour or grain, in the area. In an area of 1,000 cubic feet, the time generally required for most elfective fumigation is from about 8 to about 24 hours. In larger areas, such as grain elevators, desirable fumigation times may be about 24 to 36 hours.

In treating grain or flour, t-he toxicant is normally simply released over the 'grain or flour where it is conrained in the enclosure, suchas storage warehouses, bins, elevators and the like, and allowed to remain in the enclosed space until it has difiused and permeated it. Since the vapor is heavier than air, it tends to sink to the bottom ofthe enclosure and penetrate the grain or flour as it settles, killing the pest organisms.

The efiectiveness of perfluorodimethylperoxide as a fumigant is illustrated by the tests and results described in the following examples:

Example I Test insects were placed in 1.5 inch diameter salve tins with perforated lids. A small amount of appropriate food (grain, flour, ground dog food, etc.) was placed in each tin. Gaseous dosages in the amounts indicated were placed in ampoules and were broken in two-gallon mason jars.

- As soon as insect containers and compounds were introwith fiuorophosgene' INITIAL OR SCREENING TEST 1n the process of the invention, the pests are subjected to an atmosphere comp-rising a lethal concentration of Percent 5-day Mortality perfluorodimethylperoxide. This involves contacting the pests with the vapor of perlluorodimethylperoxide in the Confused 1 2 n kt yfi f .21

F -OO--CF Flour ea arpe ea y enclosure m Whlch tile-pests 40 per. Gal. of a Beetle Worm Bettle Worm Pupae The process of this invention is particularly applicable E1101v space to combatting pest infestation in flour, grain and other 100 100 100 100 stored products, whether contained in storage bins, grain FOLLOW-UP TESTS Percent Kill Gm. of Com- Equimltgolslggays After (1 a e in xposure li f 3 3 321. 1 ,000 it. Before Kill Confused Lesser Black Yellow Space Reading Flour Meal Carpet Meal Beetle Worm Beetle Worm 025 o. 411 3 100 100 100 100 0175 0 288 3 100 100 100 100 0. 00625 0.103 a 100 100 100 1 0 07 003 0. 049 7 100 100 100 1 70 0. 0015 0 025 7 100 100 100 1 40 B 0. 00025 0 103 3 80 100 0 s0 2 0. 003 0. 049 7 0 70 0 0 2 0.0015 0 025 7 0 0 0 1 All remaining insects near dead. 2 1,1-dichloronitroethane (a commerclal iumigant known as Ethide) used in this test in order to provide data for efiectiveness comparison.

Example II A test was also conducted against termites. The procedure and results are set forth below.

A salve tin with a perforated lid containing termite workers and a moistened paper towel strip was placed on the floor of a gallon jar and covered with a single thickness of paper toweling before burying under 4" of moist sandy soil. The dosage used was 0.025 gram per gal. of enclosed space (0.411 lb./1000 Cit- After 24 hours exposure, kill was observed.

3 Example 111 Using the same test procedure described in Example I, the results against rice weevils were as follows:

Gm. of Com- Equivalent Days After pound per dosage in Exposure Percent Gal. of lb./1,000 It. Before Kill Mortality Encl. Space Reading 0. 003 0. 049 0 100 0.0015 0.025 0 100 1 0. 003 0. 049 0 94 l 0. 003 0. 049 2 94 1 0. 003 0. 049 7 100 l 0. 0015 0. 025 0 2O 1 0. 0015 0. 025 2 60 1 0. 0015 0. 025 7 100 1 1,1dlehloronitroethane (a commerieal furnigant known as Ethide) used in this test in order to provide data for eflectiveness comparison.

Perfluorodimethylperoxide thus has been found to be anexceptionally eflective fumigant at very small dosages.

While the invention has been described with particular reference to specific embodiments, it is to be understood that it is not to be limited thereto but is to be construed broadly and restricted solely by the scope of the appended claims.

I claim:

about 0.02

to 0.4 pound per thousand cubic feet of enclosed space.

References Cited by the Examiner UNITED STATES PATENTS 12/1962 Darby et al. 260-92.1 8/ 196-3 Porter et al. 2606l0 4/ 1965 Porter et al 261610 1/ 1966 Porter et al. 260610 1/1966 Porter et a1 261-6 10 OTHER REFERENCES Porter et al.: I. Am. Chem. Soc. 79: 5625-5631 (1937).

LEWIS GOTT S, Primary Examiner.

S. K. ROSE, Assistant Examiner. 

1. A PROCESS FOR THE CONTROL OF PEST ORGANISMS INFESTING AB ENCLOSED SPACE WHICH COMPRISES SUBJECTING SAID ORGANISMS TO AN ATMOSPHERE COMPRISING A LETHAL CONCENTRATION OF PERFLUORODIMETHYLPEROXIDE. 